Method of making propeller blades



April 19, 1938. F. W. CALDWELL METHOD OF MAKING PROPELIJER BLADES Original Filed April 21, 1931 INVENTOR. FM WL'ALUWEZL 24W; 4. M I

A TTORNEY Patented Apr. 19, 1938 UNITED STATES PAT N OFFICE METl'1OD.OF MAKING PROPELLER BLADES Frank W. Caldwell, Hartford, Conn., assignor, by

mesne assignments, to United Aircraft Corporation, a corporation of Delaware 2 Claims.

This invention relates generally to propellers for aircraft, and more particularly to controllable pitch propellers for aircraft.

An object of the invention is to provide an im- 5 proved method of making and assembling controllable pitch propeller mechanism.

Fig. 1 is an elevational view, partly in section, of a propeller blade constructed in accordance with my invention.

Fig. 2 is an enlarged sectional view also showing an embodiment of the invention.

In the drawing I have shown a propeller blade I. having a shank portion ll provided with a flange 2i against which a thrust bearing 23 seats. The thrust bearing 23 seats also against the inturned portion l2 of a hub barrel 24. v v

The preferred method of manufacturing is to complete the blade with the exception of forming the flange 2|. The shank of the blade is then heated to suitable temperature and the bearing 23 is slipped loosely over the root of the heated blade and moved on the shank to a position some distance from the end of the shank. The flange II is then formed by an upsetting process in the 25 usual manner. The bearing 23 may be moved a considerable distance from the end of the shank,

permitting the upsetting of the shank end without damage to the bearing. The flange II and the exterior of the shank are then machined to provide accurate seating surfaces, after which the bearing 23 is moved down the shank toengage the seating surfaces. In case the blades used are of a light alloy requiring heat treatment after the up-setting operation to develop the full strength of the material, it is desirabie to utilize bearings made of special steel of such characteristics that its hardness is not affected by the temperature used in heat treating the metal of the blade.

This application is a division of my co-pending application, Serial No. 531,685, flied April 21, 1931, on which Patent Number 2,032,254 was granted on February 25, 1936.

The drawing and descriptions are for purposes of explanation and illustration only and not for the purpose of defining and limiting the invention, which is defined in the appended claims.

What I claim is:

1'. A method of making a blade for-a control- I lable pitch propeller that comprises -forming a blade body portion having a hollow shank, placing a bearing raceway on the shank and moving it towards the tip of the propeller beyond its operating position, upsetting the end of the shank to form a flange, machining the flange and the shank to flt the bearing, and moving the bearing onto the machined portion of the shank.

2. In the manufacture of propellers, the process which consists of forming a blade with a substantially cylindrical shank, assembling a thrust bearing over the shank, and spreading the end of the shank by an upsetting operation to form an enlarged abutment on the end of the shank for engagement with the thrust bearing.

, FRANK w. CALDWILL. 

